I would like to take this month’s theme’s (Renewable Energy) opportunity to highlight many different types of renewable energy harvesting, including some of the lesser known ones like marine energy which is a very promising aspect of energy technology that can make a big difference. I would also cover the UK's current recent efforts and advancements in the use of alternative energy.

Alternative energy is any energy source that is an alternative to fossil fuel. These alternatives are intended to address concerns about such fossil fuels, such as its high carbon dioxide emissions, an important factor in global warming.

The use of alternative energy has many potential benefits, including a reduction in greenhouse gas emissions, the diversification of energy supplies and a reduced dependency on fossil fuel markets (in particular, oil and gas). Examples of alternative energy are: wind, solar, biomass, wave and tidal energy.

Solar Energy

Solar is the first energy source in the world. It was in use much earlier before humans even learn how to light a fire. Many living things are dependent on solar energy from plants, aquatic life and the animals. The solar is mostly used in generating light and heat. The solar energy coming down to the planet is affected by the orbital path of the sun and its variations within the galaxy. In addition, it is affected by activity taking place in space and on the sun. It was this energy that is believed to have been responsible for the breaking of ice during the ice age, which creates the separation of lands and sea.

Solar energy is one the alternative energy source that is used most widely across the globe. About 70% of the sunlight gets reflected back into the space and we have only 30% of sunlight to meet up our energy demands. While solar energy is used for producing solar energy, it is also used for drying clothes, used by plants during the process of photosynthesis and also used by human beings during winter seasons to make their body temperature warm. Solar energy can be extracted either by Solar Thermal or using Photovoltaic (PV) Cells.

There are two kinds of solar energy the active solar energy and the passive solar energy. Passive solar energy basically uses duration, position and sun's rays intensity to its advantage in heating a particular area. It also uses it to induce airflow from an area to the next. Active solar energy uses electrical technology and mechanical technology like collection panels in capturing, converting and storing of energy for future use.

Solar energy does not create any pollution and is widely used by many countries. It is renewable source of power since sun will continue to produce sunlight all the years. Solar panels, which are required to harness this energy can be used for long time and require little or no maintenance. Solar energy proves to be ineffective in colder regions which don't receive good sunlight. It cannot be used during night and not all the light from sun can be trapped by solar panels. Solar energy advantages are much more than its disadvantages which make it as a viable source of producing alternative energy.

Wind Energy

This is one of the energy sources that have been in use for a very long time and for centuries. It was used in powering sailing ships, which made it possible for explorers to sail around their trade routes in distant lands. A single windmill can power the crop irrigation, and the family energy needs, water pumping and electric lights. However, in the present time there are several windmills that are used to generate required energy mostly for industrial uses. Many of the wind turbines can capture much power all at once before feeding it to the power grid. This is commonly known as wind farms and has been in use for many years all round the world. It is only the United States that is going slow in terms of accepting this alternative energy source.

Wind power is renewable source of energy and reduces our alliance on foreign countries for supply of oil and gas. It does not cause any air pollution and have created several jobs in last few decades. Advancement in technologies has brought down the cost of setting up wind power plant. Wind energy can only be used in areas which experience high winds which mean that it cannot be used as a source to extract energy anywhere on earth. They sometimes create noise disturbances and cannot be used near residential areas. These disadvantages have made the use of wind energy to particular regions only.

Due to abundant winds throughout the year, wind power is commonly used in European part of the world. As of December 2014, installed capacity of wind power in the European Union totalled 128,751 megawatts (MW). The EU wind industry has had a compound annual growth rate of 10% between the years 2000 and 2013. In 2014, a total of 11,791 MW of wind power was installed, representing 32% of all new power capacity. In a normal wind year the wind power capacity installed by early 2014 would produce 257 TWh of electricity, enough to supply 8% of the EU's electricity consumption.

Wind power in Denmark provides some 39 percent of Danish domestic electricity and Denmark is a leading wind power nation in the world. At the beginning of 2013, the installed capacity of wind power in the United Kingdom was 8,445 megawatts (MW), with 362 operational wind farms and 4,158 wind turbines in the United Kingdom. The United Kingdom is ranked as the world's eighth largest producer of wind power.

1.8 GW of new wind power capacity was brought online during 2012, a 30% increase of the total UK installed capacity. 2012 was a significant year for the offshore wind industry with 4 large wind farms becoming operational with over 1.1 GW of generating capability coming on stream.[32]

Through the Renewables Obligation, British electricity suppliers are now required by law to provide a proportion of their sales from renewable sources such as wind power or pay a penalty fee. The supplier then receives a Renewables Obligation Certificate (ROC) for each MW-h of electricity they have purchased. Within the United Kingdom, wind power is the second largest source of renewable energy after biomass.

Wind power is expected to continue growing in the United Kingdom for the foreseeable future – RenewableUK estimated in 2010 that more than 2,000 MW of capacity would be deployed per year for the next five years. By 2020, the United Kingdom is expected to have more than 28,000 MW of wind capacity. 

Geothermal Energy

'Geo' means Earth and 'thermal' means energy. Geothermal energy means energy drawn or harnessed from beneath the earth. It is completely clean and renewable. Geothermal energy has been in used since last several years. The earth contains a molten rock called magma. Heat is continuously produced from there. The temperature increases about 3 degrees Celsius, for every 100 meters you go below ground. Below, 10,000 meters the temperature is so high, that it can be used to boil water. Water makes its way deep inside the earth and hot rock boils that water. The boiling water then produces steam which is captured by geothermal heat pumps. The steam turns the turbines which in turn activates generators.

Geothermal energy can be found anywhere on the earth. Most countries tap this energy to generate electricity, using thermal mass flowmeters, and power millions of homes. The areas which have high underground temperatures are the ones which are the ones which are prone to earthquakes and volcanoes. The United States produces more Geothermal electricity than any other country in the world. Most hot water geothermal reservoirs are located in the western states, Alaska, and Hawaii. Geothermal energy is totally renewable as earth will continue to produce heat as long as we are all are here. If these resources are tapped and are utilized effectively, they can provide solution to the world's power problems.

Geothermal energy produces no pollution, reduces our alliance on fossil fuels. It also results in significant cost savings as no fuel is required to harness energy from beneath the earth. These advantages make geothermal energy as one the best alternative energy source. But, geothermal has its downsides too. It is suitable to particular region and cannot be harnessed everywhere. The earth may release some harmful gases while releasing the heat which may prove adverse from mankind. Also, the areas where this energy is harnessed are prone to earthquakes and volcanoes. Apart from that, setting up of geothermal power stations requires huge installation cost. Here are some prosand cons of geothermal energy.

Hydroelectric Energy

Solar energy is produced by sun and wind energy is produced by moving of winds. The heat caused by sun drives the wind. The movement of winds is then captured by wind turbines. Both wind and sun cause water to evaporate. The water vapor then turns into rain or snow and flows down to sea or oceans through rivers or streams. The energy of the moving water can then be captured and called as hydroelectric power. Hydroelectric power stations capture the kinetic energy of moving water and give mechanical energy to turbines. The moving turbines then convert mechanical energy into electrical energy through generators. Dams around the world have been built for this purpose only. Hydropower is the largest producer of alternative energy in the world.

There are different types of hydropower plants. The selection of hydropower plant depends on many volume and flow of water. Hydropower is renewable, constant, predictable and controllable source of energy. They emit no greenhouse gases and are environment friendly. On the negative side, they may cause adverse effect on aquatic life, reduce flow of water which may affect agriculture, require huge costs to build and may cause havoc if they get breakdown.

Biomass Energy

This is the process by which an alternative energy is generated through conversion of biological materials and wastes into forms that can be used as energy sources for heating, power generation and transportation. Those carbon based substances or materials converted over a long period of time to fossil fuels are not regarded as biomass. However, in their original state they are regarded as biomass. This is because of the separation of the carbon they previously contained from the carbon cycle. This makes them figure differently affecting carbon dioxide levels in air.

Biomass energy has been around since ancient times when people use to burn wood or coal to heat their homes or prepare food. Wood still remains the most common source to produce biomass energy. Apart from wood, the other products that are used to create biomass energy include crops, plants, landfills, municipal and industrial waste, trees and agricultural waste. Biomass is renewable source of energy as we would be able to produce it as long as crops, plants and waste exist. It does not create any greenhouse gases and is can be easily extracted through the process of combustion. Another advantage of biomass is that it helps to reduce landfills. Biomass is comparatively ineffective as compared to fossil fuels. They release methane gases which can be harmful to the environment.

Ocean Energy

The earth promises many power sources. Just like the geothermal and solar energy, which have long been used in heating homes and lighting as well when harnessed. Even in the last century these forms of energy was in use. Due to massive size of oceans, this energy can be used on much wider scale than other alternative sources of energy. The waves produced by the ocean and tides that hit the sea shore has enormous potential in them. If they are harnessed with full capacity they can go a long way in reducing world's energy problems. There are 3 ways i.e. Tidal energy, Wave energy and Ocean thermal energy conversion (OTEC) via which ocean energy can be harnessed.

Tidal power basically involves using kinetic energy from the incoming and outgoing tides. The difference in high tides and low tides are also important in this respect. There is a lot of energy that can be harnessed from waves for use. It is another form of hydropower. The rise and fall of ocean tides are captured by tidal energy generators which turn turbines. The movement of turbines is responsible for producing electricity. In short, tidal energy generator captures the kinetic motion of the tides and converts them into electrical energy. The main advantage of tidal energy is that it is completely renewable and are much more predictable than wave energy.

 Hydrogen Energy

Hydrogen is the most abundant element available on earth but it is rarely alone. Even water contains two third of hydrogen. It is usually available with other elements and have to separated before we can make use of it. Hydrogen has tremendous potential and can be used to power up homes, vehicles and even space rockets. It takes a lot of energy to separate hydrogen from other elements and therefore it proves to quite expensive to extract it. Take a close look at hydrogen energy and see how it works.

The main benefit of hydrogen energy is that it is clean source of fuel and does not leave any waste elements behind except water. There are no harmful emissions and is environment friendly. It is completely renewable and can be produced over and over again on demand. Hydrogen can also be used to make bombs like the ones used by America on Hiroshima and Nagasaki which makes it highly inflammable. Dependency on fossil fuels still remains as we need them to extract hydrogen from other elements. Also, it is quite expensive to produce and store.

Alternative (Renewable) energy in the EU

Alternative (Renewable) energy in the EU has grown strongly in recent years. More concretely, the share of energy from renewable sources in gross final energy consumption has almost doubled in the last years, from around 8.5 % in 2004 up to 16.7 % in 2015.

The 2020 climate and energy package adopted in EU in December 2008 provided a further stimulus for increasing the use of renewable energy sources to 20 % of total energy consumption by 2020, while calling for energy consumption and greenhouse gas emissions to both be cut by 20 %. Directive 2009/28/EC of the European Parliament and Council on the promotion of the use of energy from renewable sources set an overall goal across the EU for a 20 % share of energy consumption to be derived from renewable sources by 2020, while renewables should also account for a 10 % share of the fuel used in the transport sector by the same date. The Directive changes the legal framework for promoting renewable electricity, requires national action plans to show how renewable energies will be developed in each EU Member State, creates cooperation mechanisms, and establishes sustainability criteria for liquid biofuels (following concerns over their potential adverse effects on crop prices, food supply, forest protection, biodiversity, water and soil resources). 

This positive development has been prompted by the legally binding targets for increasing the share of energy from renewable sources enacted by Directive 2009/28/EC on the promotion of the use of energy from renewable sources. While the EU as a whole is on course to meet its 2020 targets, some Member States will need to make additional efforts to meet their obligations as regards the two main targets.

The primary production of renewable energy within the EU-28 in 2015 was 204 million tonnes of oil equivalent (toe). The quantity of renewable energy produced within the EU-28 increased overall by 70.2 % between 2005 and 2015, equivalent to an average increase of 5.5 % per year.

Among alternative energies, the most important source in the EU-28 was wood and other solid biofuels as well as renewable wastes, accounting for 44.0 % of primary renewables production in 2015. Hydro power was the second most important contributor to the renewable energy mix (14.4 % of the total), followed by wind power (12.7 %). Although their levels of production remained relatively low, there was a particularly rapid expansion in the output of wind and solar power, the latter accounting for a 6.4 % share of the EU-28's renewable energy produced in 2015, while geothermal energy accounted for 3.2 % of the total. There are currently very low levels of tide, wave and ocean energy production, with these technologies principally found in France and the United Kingdom.

Summary

Wind energy is really clean and renewable as it doesn't leave any residues. Geothermal energy is usually used for space heating or heat pump! Biomass energy is quite interesting and has a great potential as we can turn waste to be useful stuff! Ocean energy, same as marine energy, is also interesting. If we can develop very strong and stable device or material that could sustain in harsh marine environments, maybe this energy harvesting will become an innovative method to generate power.

Sources

https://www.bp.com/en/global/corporate/media/press-releases/bp-alternative-energy-announcement-december-2017.html

http://ec.europa.eu/eurostat/statistics-explained/index.php/Renewable_energy_statistics

https://www.conserve-energy-future.com/alternativeenergysources.php